<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<script src="https://unpkg.com/eventemitter3@latest/dist/eventemitter3.umd.min.js"></script>
<script src="../dist/RosLib.umd.cjs"></script>

<script>
  // Connecting to ROS
  // -----------------
  var ros = new ROSLIB.Ros();

  // If there is an error on the backend, an 'error' emit will be emitted.
  ros.on('error', function(error) {
    document.getElementById('connecting').style.display = 'none';
    document.getElementById('connected').style.display = 'none';
    document.getElementById('closed').style.display = 'none';
    document.getElementById('error').style.display = 'inline';
    console.log(error);
  });

  // Find out exactly when we made a connection.
  ros.on('connection', function() {
    console.log('Connection made!');
    document.getElementById('connecting').style.display = 'none';
    document.getElementById('error').style.display = 'none';
    document.getElementById('closed').style.display = 'none';
    document.getElementById('connected').style.display = 'inline';
  });

  ros.on('close', function() {
    console.log('Connection closed.');
    document.getElementById('connecting').style.display = 'none';
    document.getElementById('connected').style.display = 'none';
    document.getElementById('closed').style.display = 'inline';
  });

  // Create a connection to the rosbridge WebSocket server.
  ros.connect('ws://localhost:9090');

  // Publishing a Topic
  // ------------------

  // First, we create a Topic object with details of the topic's name and message type.
  var cmdVel = new ROSLIB.Topic({
    ros : ros,
    name : '/cmd_vel',
    messageType : 'geometry_msgs/Twist'
  });

  // Then we create the payload to be published. The object we pass in to ros.Message matches the
  // fields defined in the geometry_msgs/Twist.msg definition.
  var twist = {
    linear : {
      x : 0.1,
      y : 0.2,
      z : 0.3
    },
    angular : {
      x : -0.1,
      y : -0.2,
      z : -0.3
    }
  };

  // And finally, publish.
  cmdVel.publish(twist);

  // Subscribing to a Topic
  // ----------------------

  // Like when publishing a topic, we first create a Topic object with details of the topic's name
  // and message type. Note that we can call publish or subscribe on the same topic object.
  var listener = new ROSLIB.Topic({
    ros : ros,
    name : '/listener',
    messageType : 'std_msgs/String'
  });

  // Then we add a callback to be called every time a message is published on this topic.
  listener.subscribe(function(message) {
    console.log('Received message on ' + listener.name + ': ' + message.data);

    // If desired, we can unsubscribe from the topic as well.
    listener.unsubscribe();
  });

  // Calling a service
  // -----------------

  // First, we create a Service client with details of the service's name and service type.
  var addTwoIntsClient = new ROSLIB.Service({
    ros : ros,
    name : '/add_two_ints',
    serviceType : 'example_interfaces/AddTwoInts'
  });

  // Then we create a Service Request. The object we pass in to ROSLIB.ServiceRequest matches the
  // fields defined in the rospy_tutorials AddTwoInts.srv file.
  var request = {
    a : 1,
    b : 2
  };

  // Finally, we call the /add_two_ints service and get back the results in the callback. The result
  // is a ROSLIB.ServiceResponse object.
  addTwoIntsClient.callService(request, function(result) {
    console.log('Result for service call on ' + addTwoIntsClient.name + ': ' + result.sum);
  });

  // Advertising a Service
  // ---------------------

  // The Service object does double duty for both calling and advertising services
  var setBoolServer = new ROSLIB.Service({
    ros : ros,
    name : '/set_bool',
    serviceType : 'std_srvs/SetBool'
  });

  // Use the advertise() method to indicate that we want to provide this service
  setBoolServer.advertise(function(request, response) {
    console.log('Received service request on ' + setBoolServer.name + ': ' + request.data);
    response['success'] = true;
    response['message'] = 'Set successfully';
    return true;
  });

  // Getting a param value
  // ---------------------

  // In ROS 2, params are set in the format 'node_name:param_name'
  var favoriteColor = new ROSLIB.Param({
    ros : ros,
    name : '/add_two_ints_server:use_sim_time'
  });

  favoriteColor.get(function(value) {
    console.log('The value of use_sim_time before setting is ' + value);
  });
  favoriteColor.set(true);
  favoriteColor.get(function(value) {
    console.log('The value of use_sim_time after setting is ' + value);
  });
</script>
</head>

<body>
  <h1>Simple roslib Example</h1>
  <p>Run the following commands in the terminal then refresh this page. Check the JavaScript
    console for the output.</p>
  <ol>
    <li><tt>ros2 topic pub /listener std_msgs/msg/String "{ data: 'hello world' }" </tt></li>
    <li><tt>ros2 topic echo /cmd_vel</tt></li>
    <li><tt>ros2 run demo_nodes_py add_two_ints_server</tt></li>
    <li><tt>ros2 launch rosbridge_server rosbridge_websocket_launch.xml</tt></li>
  </ol>
  <div id="statusIndicator">
    <p id="connecting">
      Connecting to rosbridge...
    </p>
    <p id="connected" style="color:#00D600; display:none">
      Connected
    </p>
    <p id="error" style="color:#FF0000; display:none">
      Error in the backend!
    </p>
    <p id="closed" style="display:none">
      Connection closed.
    </p>
  </div>
</body>
</html>
